Polyvinyl acetal composition



sharply with a 1 /2 pound. hammer. examination failed to revealthe presence of any Patented May 14, 1946 UNITED STATES 2.4003 romzvnwr. nearer. oourosmon PATENTJ OFFICE I Franklin A. Bent, Berkeley, and Kenneth E. Marple, Oakland, Calif., assignors to Shell Development Company,

San Francisco, Calif., a

corporation of Delaware No Drawing; Application April 9, 1943. Serial No. 482,514

4 Claims. (c1. zoo-so) This invention relates to organic plastic compositions containing glycidyl ethers of glycerol as plasticizers.

An object of the invention is the production of novel compositions comprising organic plastic 5 material. Another object is'the production of compositions which can be made into thin transparent films of exceptional strength, flexibility and toughness. A further object is the formation of compositions suitable for the preparation 1 with this invention by the use of glycerol glycidyl g0 ethers and thio-ethers as plasticizers for organic plastic material. It has been found that there can be formed from cellulose derivative and synthetic resin compositions containing glycerol mono-,- di-, and tri-glycidyl ethers clear, wateras white structures of high tensile strength, toughness and-flexibility, and that these properties are retained even at sub-zero temperatures.

The following examples, in which parts and percentages are given by weight, will illustrate the invention: I

I Example I Polyvinyl butyral resin marketed as Vinylite X was blended with 50 parts of glycerol-a, 'y- 35 di(methyl isobutyl carbinyl) -pglycidyl ether per 100 parts of resin. A sheet wasformed by milling the composition between heated rolls,

7 followed by pressing between hot, polished metal platens. water-white, highly flexible and tough. A strip 8 inches long, 2% inches wide'and 0.03 inch thick was subjected to a chill test? in which the strip was doubled over on itself to /2 its length and held at 0' F. for 4 hours. The folded edge was 4 then placed upon a flat wooden block and struck Careful 1 cracks or fractures. Another portion of the material was used in making safety glass which 50 satisfactorily passed a standard break test at o n, '10" F. and 120 Example II I which can be serve to The material was perfectly clear,

mark "Butvar was blended with parts of glycerol-en-dflbutyl cellosolve) -p-glycidyl ether. A sheet formed from the composition did not fracture when subjected to the "chill test.

Example III 20 of the plasticizer-containing composition of Example I were dissolved in parts of a mixture of equal proportions of acetone and methanol. The solution was cast in a thin layer upon a. glass plate, the solvent was removed by evaporation and the resulting film was stripped from the glass surface. The film was used as an interlayer in a laminated glass, which satisfactorily passed a break test at 0? F.

Example IV Vinylite X" polyvinyl butyral resin was homogeneously mixed with glycerol-a-butyl-pglycidyl-q-(methyl isobutyl carbinyl) ether in proportions of 2'parts of resin to 1 of the ether. Safety glass was formed by the autoclave method using an extruded sheet of the composition as interlayer, without added adhesive. when the glass laminae of the safety glass were broken with a hammer at room temperature. the interlayer adhered perfectlyjto the separate pieces.

The test was repeated-at 0 F. and at F. with the same result. An unbroken section of the safety glass was exposed to weathering under acceleratedconditions. At the end of 6 months substantially no discoloration was apparent and there was no separation of the edges of the laminae. a v

The compositions of the present invention are homogeneous mixtures of organic plastic mate-.

rial and glycerol glycidyl ethers or thio-ethers. Examples of plastics-which may be used are cellulose nitrate, cellulose acetate, cellulose acetopropionate, cellulose acetobutyrate, ethyl cellulose, benzyl cellulose, urea-formaldehyde, phenol-formaldehyde, alkyd resins, polystyrene, polyvinyl acetate, co-polymers of vinyl acetate and vinyl chloride, polyvinyl acetals, and acrylic resins, such as polymethyl methacrylate.

The preferred plastics are the polyvinyl acetal resins, which-can be produced by the partial or complete hydrolysis of a polyvinyl ester, followed by the condensation of the resulting polyvinyl alcohol or partial polyvinyl alcohol with an aldehyde. In this application the term acetal is used to designate also mixed acetals, ketals, and mixed acetal-ketals. Mixed acetals result from the condensation of olyvinyl alcohol with more Polyvinyl butyral resin sold under the trade 88 than p one aidehyda Ketal formation involves naphthyl,

The plasticizers of the invention have the structure represented by the general formula:

. CHI-x34 n-xm Hg-XR;

wherein X is O or S and R1,R2 and R3 are the same or different and are hydrogen or organic radicals, at least one being the glycidyl radical. As organic radicals may be mentioned alkyl, alkenyl, alkynyl, alkoxy-alkyl, aralkyl, aryl, acyl, alicyclic, alicarbocy'clic, and heterocyclic radicals.

Specifi examples of such radicals are methyl,

ethyl, propyl, isopropyl, normal butyl, isobutyl,

secondary butyl, tertiary butyl, normal pentyl, isopentyl, secondary pentyl, hexyl, normal octyl, iso-octyl, normal decyl, isodecyl, dodecyl, tetradecyl, cetyl, stearyl, trimethyl octodecyl, allyl, methallyl, crotyl, methyl vinyl carbinyl, butenyl, pentenyl, hexenyl, propargyl, geranyl, oleyl, phenyl, naphthyl, anthryl, tolyl, xylyl, secondary butyl-naphthyl, dipropyl-naphthyl, benzyl, naphthylbutyl, phenethyl, vinyl-phenyl, crotonylmethallyl-phenyl, triallyl-naphthyl, naphthylallyl, 2-phenylethenyl, phenyl vinyl carbinyl, cinnamyl, acetyl, propionyl, capro-yl, stearacyl, benzoyl, cyclopentyl, ethyl-cyclohexyl, tributyl-cyclohexyl, cyclopentenyl, cyclohexenyl, vinyl cyclohexenyl, thioenyl, pyrrolyl, pyridyl, furyl, butyl carbothionyl, octyl carbothionyl, decyl carbothionyl, etc. Further, these radicals may be substituted with other elements or groups as halogen, hydroxyl, amino, nitro, carbonyl, sulfo, cyano, etc. For example, such substituted radicals may be chlorobutyl, promo-octyl, nitroethyl, hydroxycyclohexyl, nitrobenzyl, chlorallyl, chlorobenzoyl,

tetrahydrofurfuryl, hydroxyethyl, dihydro-isophoryl, sulfa-ethyl, benzene sulfonyl, cyanoacetyl, etc. A preferred sub-group of plasticizers consists of the saturated alkyl and saturated alkoxy-alkyl diethers of glycerol-p-glycidyl ether. These compounds may be represented by the formula:

. CHI-0R1 H 0CHzCHCHz HrOR: 0

wherein R1 and R2 ar the same or different saturated alkyl or alkoxy-alkyl radicals.- Of this subgroup, those compounds in which the sum of the number of carbon atoms in the two alkyl or alkoxy-alkyl radicals is at least 9 are favored. Compositions containing them are free from exudation, resistant to aging and exhibit low loss in weight even over long periods of time. Because of these and other properties many of them are suitable for use in safety glass interlayers.

As examples of saturated alkyl and alkoxyalkyl di-ethers of glycerol-beta-glycidyl ether may be mentioned: -glycerol-oz-y-diamyl-p-glycidyl ether, glycerol-a-y-dihexyl-p-glycidyl ether, glycerol-u-y-dflmethyl propyl carbinyl)-fl-glyc of solvent.

idyl ether, glycerol-a-y-dflmethyl isopropyl carbinyl) -,8-g ycidy1 ether, lycerol-a-v-dflmethyl butyl carbinyl)-fl-glycidyl ether, glycerol-awdi(methyl isobutyl carbinyl)-p-glycidyl ether, glycerol-a-v-biswiethyl carbinyl) p glycidyl ether, glycerol-a-y-dflpropyl cellosolve) -p-glycidyl ether, glycerol-a-v-dflbutyl cellosolve)-,6- glycidyl ether, glycerol-e-v-difisobutyl cellosolve) -p-glycidyl ether, glycerol-a-y-dflmethoxy butyll-fl-glycidyl ether, glycerol-a-v-dflethoxy propyl) -fi-glycidyl ether, glycerol-a-y-dflbutoxy propyD-p-glycidyl ether, glycerol-u-v-dflbutoxy butyDp-glycidyl ether, glycerol-a-propyl-fl-glycidyly-(methyl butyl carbinyl) ether, glycerol-uisopropyl-fl-glycidylq- (methyl isobutyl carbinyl) ether, glycerol-a-(butyl cellosolve) -fi-glycidyl-'ybutyl ether and glycerol-u- (butoxy butyl) -fi-8lycidyl-y-butyl ether.

In the case of polyvinyl acetals, the plasticizers may be incorporated with the resin by mixing with the polymer prior to or during the step of condensation with the aldehyde. With all plastics they may be conveniently added by grinding, mixing or milling, or by the use of heated rolls. Volatile solvents may be used to facilitate blending, particularly where the preparation of coating compositions is involved.

' The amount of plasticizer employed may vary widely according to the nature and the intended use of the composition. Molded articles ordinarily require less plasticizer than coating compositions and safety glass interlayers. Amounts of a glycerolglycidyl ether as small as 5% by weight of the total composition impart noticeable plasticity thereto. On the other hand, complete compatibility and freedom from exudation characterize compositions in which the plasticizer is present in an amount as great as 75% by weight of the total. For safety glass interlayers the amount of plasticizer will ordinarily vary from about 25% to about 45% by weight of the total composition.

The glycerol glycidyl ethers may be used alone or in conjunction with small amounts of other plasticizers. Where molding, coating and impregnating compositions are involved, there may be added titanium dioxide, zinc oxide, carbon black, wood flour and other common pigments and fillers, as well as dyes and other modifiers. Polyvinyl acetal resins are advantageously stabilized against decomposition by the addition of a small amount of an organic base or other stabilizing substance known to those skilled in the art.

The plasticizers of the present invention show little tendency to evaporate from the prepared compositions containing them, even over .long periods of time. The loss due to volatility in blending on heated equipment is small.

The compositions of the invention find use in I a variety of applications. In granular and pellet form they serve for compression and injection molding. Filaments and films may be formed by dry or wet spinning in the presence or absence Solutions of the compositions may be cast in thin layers upon a polished surface, followed by the evaporation of the solvent. Films so formed find use as supports for light-sensitive photographic emulsions, for wrapping tissues and for the manufacture of shatter-proof glass.

Shaped structures comprising polyvinyl acetal resins plasticized with glycerol glycidyl ethers are clear and water-white. They possess high tensile strength and flexibility even at low temperatures. The polyvinyl butyral compositions included in the ambit of this invention display remarkable adhesiveness for glass in the preparation of safety glass sandwiches with heat and pressure in accordance with any of the usual methods. This adhesiveness is retained in the prepared product even at sub-zero temperatures.

Solutions of compositions comprising polyvinyl acetals and glycerol glycidyl ethers are used for the coating and impregnating of fabric. Material so formed is ideally adapted for the manufacture of raincoats, tents and other articles which are required to be water-proof. For this purpose, it is preferred to modify the polyvinyl acetal resin by the incorporation of a small amount of a 10 thermosetting resin.

We claim as our invention:

1. A composition comprising a polyvinyl acetal and a glycidyl ether of glycerol.

2. A composition adapted for use in safety glass interlayers comprising a polyvinyl butyral resin and a glycidyl other of glycerol.

8. A composition comprising a polyvinyl acetal resin and an ether of glycerol wherein the hydrogen atom of one of the hydroxyl groups is substituted by a glycidyl radical and the hydrogen atoms of the other two hydroxyl groups are substituted by alkyl groups. a

4. A composition comprising a polyvinyl acetal resin and 25 to 45 per cent by weight of glycerolu,'y-di(methyl isobutyl carbinyl) -fi-glycidyl ether.

FRANKLIN A. BENT KENNETH E. MARPLE. 

